Diagnosis and Management of Orbital Fat Exposure During Endoscopic Sinus Surgery

Abstract

Background:

The orbital complication rate during endoscopic sinus surgery (ESS) is <1%. Orbital fat exposure during ESS can herald orbital complications including orbital hematoma, extraocular muscle trauma, optic nerve injury, or blindness. The objective of this study was to evaluate the current consensus regarding diagnosis and management of orbital fat exposure during ESS.

Methods:

A 24-point survey focused on orbital fat exposure during ESS was distributed to American Rhinologic Society members. Also, a retrospective review of 25 cases of orbital fat exposure drawn from the principal investigator’s 30-year experience was performed.

Results:

Over 10 000 surgical cases of the principal investigator were reviewed. Twenty-five patients had orbital fat exposure. Five developed minor complications while 2 were major (ie, temporary vision changes). Two hundred thirty-six surgeons responded to the survey; 93% had encountered orbital fat during ESS; 88% of surgeons identify orbital fat by either its appearance endoscopically or the “bulb press” test. Almost every responding surgeon will cautiously avoid further manipulation in the area of orbital fat exposure. Nearly half will immediately curtail the extent of surgery. Surgeons do not significantly change postoperative management. Considerations regarding observation in postanesthesia care unit, close follow-up, and strict nose blowing precautions are common.

Conclusion:

Orbital fat exposure during ESS is a rarely discussed, but clinically important. Orbital fat exposure can be a harbinger for major orbital complications that should be recognized by endoscopic appearance and confirmed with the bulb press test. Caution with “no further manipulation” of orbital fat is the guiding principle for intraoperative management, while postoperative management is generally expectant.

Level 4 Evidence

Introduction

An estimated 600 000 sinonasal surgical procedures were completed in the ambulatory surgical setting in 2006 alone. Of these, an estimated 260 000 were endoscopic sinus surgery (ESS), making ESS one of the most common ambulatory surgeries in the United States. ¹ The field of rhinology has undergone rapid evolution since the introduction of ESS in 1985, which effectively revolutionized the surgical treatment of sinonasal disease. Many of the first recognized surgical complications that accompanied the widespread adoption of ESS were outlined by the principal investigator during the infancy of ESS. ^{2 -7} These seminal studies contributed to the excellent safety profile of sinus surgery in today’s modern practice.

Complications related to ESS may be divided into minor and major categories. Minor complications include epistaxis, hyposmia, adhesions, headache, and periorbital bruising. Major complications include large volume epistaxis, carotid artery injury, orbital hematoma, extraocular muscle injury with diplopia, blindness, and cerebrospinal fluid leak with, or without, brain injury. ² In large database reviews, the risk of major complications during ESS is found to be ∼1%. ^8,9 Despite this excellent safety profile, the large volume of sinus surgeries performed annually in the United States can translate into thousands of major complications.

A less-described entity in the literature, but well-known to the practicing rhinologist, is orbital fat exposure during ESS. Orbital fat exposure signifies a violation of the lamina papyracea and to the vigilant surgeon serves as a harbinger for major orbital complications such as extraocular muscle trauma, optic nerve injury, retrobulbar hemorrhage, and/or blindness. ^10,11

The objectives of this study were to better understand the clinical impact of orbital fat exposure, offer straightforward methods of diagnosis and management, and discuss the practical considerations for the Otolaryngologist when orbital fat is inevitably encountered during ESS.

Methods

This study was completed, in part, by surveying members of the American Rhinologic Society (ARS). A 24-point itemized questionnaire with a mixture of multiple choice and free response questions was created. Questions focused on surgeon experience, encounters with orbital fat, intraoperative management, and postoperative management (Figure 1). The survey was dispersed to all members of the ARS with the approval of the ARS Board of Governors. Respondents submitted responses voluntarily.

Figure 1.

Example of a survey distributed to the members of the ARS focused on surgeon experience, encounters with orbital fat, diagnosis and management. ARS indicates American Rhinologic Society.

In addition, a retrospective chart review drawing from the principal investigator’s 30+ year ESS experience identified 25 cases of orbital fat exposure. Clinicoradiographic data for each case was collected with a focus on intraoperative diagnosis, intraoperative management, postoperative management, and surgical follow-up.

Results

American Rhinologic Society Survey

The survey was completed by 236 respondents. There was a healthy mix of practice settings: 38% academic, 49% community/private, 13% hybrid, and less than 1% government. Over three-quarters (78%) of respondents reported completing at least 500 ESS in their career; 40% completed between 1000 and 5000 cases, while 10% reported 5000 to 20000 cases in their career. Median ESS cases was 1000.

Two hundred and twenty-one of the 237 respondents (∼93%) reported encountering orbital fat during ESS. The range of instances in which orbital fat was encountered was 0 to 200. Of the respondents who had encountered orbital fat, 50% had encountered orbital fat 5 times or more.

The preferred method for intraoperative recognition of orbital fat was by its appearance endoscopically (88%) and/or via the bulb press test (85%). A minority of surgeons (6%) used a “fat float test” (ie, fat floats in saline) to diagnose orbital fat.

When questioned regarding intraoperative management, 189 of 208 respondents (90%) prefer “no further manipulation,” while a minority of respondents (10%) use bipolar cautery to reduce the fat. When specifying “other” techniques, a minority (9%) of surgeons will elect to gently place a hemostatic agent (eg, gelfoam or surgicel) to cover the fat. In addition, silastic sheeting and septal cartilage are mentioned as alternative means to cover/repair the defect.

Based on responses regarding the presence of complications secondary to orbital fat exposure, the most common to least common complications were as follows: orbital ecchymosis > orbital emphysema > orbital hematoma > medial rectus trauma > superior oblique or inferior rectus trauma > blindness.

Based on respondents own estimated rates of complications following orbital fat exposure, orbital ecchymosis was present in an average of 26% of cases (11% median), orbital emphysema an average of 7%, orbital hematoma 2.4%, diplopia 1.9%, rectus muscle trauma <1%.

Regarding consideration of surgical decompression of the orbit, 48% reported the decision to consider a canthotomy/cantholysis would depend on suspected orbital hematoma; 27% would consider a canthotomy/cantholysis in the event of increasing intraorbital pressure; 21% reported they would consider a canthotomy/cantholysis in the event of proptosis.

Eighty-six of 207 respondents (42%) would immediately alter operative management if there was evidence of orbital fat exposure during ESS. Although answers varied, >95% stated they would proceed with extreme care to limit any additional dissection near the orbital fat exposure. Other responses included “avoid the area,” “reduce/remove microdebrider on affected side,” “be conservative”. This could include halting surgery on the affected side or even terminating the procedure (in a minority of respondents).

The majority of respondents (63%) use caution and close-monitoring in the postanesthesia care unit (PACU) to determine course of action following orbital fat exposure during ESS. While 27% of respondents would not alter postoperative course at all; 16% of respondents would arrange closer follow-up. In addition, many free responses emphasized the importance of counseling to avoid nose blowing and sneezing precautions.

Seventy-three percent of respondents do not significantly alter postoperative follow-up schedules, while 27% do alter the routine follow-up. Free response alterations of postoperative care included same day follow-up in clinic, follow-up daily, daily phone calls, or follow-up in 2 to 3 days. Over half of respondents (55%) noted that orbital fat exposure during ESS would modify postoperative debridement and would exercise caution around the orbital fat exposure.

Case Series

In the retrospective portion (Table 1), a total of 25 cases of orbital fat exposure were identified in the principal investigator’s 30+ year experience of over 10 000 cases. Seven cases had evidence of complications from orbital fat exposure. Five of these 7 cases with complications were during revision cases. In addition, 5 of these 7 cases with complications were minor and limited to bruising, crepitus, or eyelid edema. Only 2 of the 7 complications were major with temporary vision changes (circa 1986 and 1993). Administration of mannitol, eye massage, and an ophthalmology consult were utilized in these 2 cases. A lateral canthotomy was performed in a single case for suspected retrobulbar hematoma. This surgery took place in 1986. There were zero cases of permanent changes in vision. In 5 instances, the orbital fat was trimmed, and this occurred more frequently during the earlier years of ESS practice. The most employed intraoperative management was “no further manipulation.” Four patients had closer follow-up (defined as <7 days) and these same 4 patients were prescribed steroids (oral vs drops) during the immediate postoperative period. In 20 of 25 cases, the orbital fat was observed, and no further manipulation was undertaken during surgery with no postoperative complications.

Table 1.

Summary of 7 Orbital Complications Following Orbital Fat Exposure During ESS.^a

Patient	Complication	Laterality	Image guidance	Intraoperative	Postoperative
1	Temporary vision changes	Left	N	Lateral canthotomy, external ethmoid approach, ligation of AEA, medial orbital wall decompression	Inpatient admission, close follow-up
2	Lower lid ecchymosis	Left	Y	Avoid further manipulation	Routine follow-up
3	Lower lid ecchymosis	Left	Y	Avoid further manipulation	Close follow-up (POD3)
4	Lower lid ecchymosis	bilateral	Y	Avoid further manipulation	Close follow-up (POD5)
5	Lower lid ecchymosis	left	N	Avoid further manipulation	Routine follow-up
6	Temporary vision changes	bilateral	N	Mannitol, massage, ophtho consult, orbital fat trimmed	Close follow-up
7	Lid ecchymosis and crepitus	unknown	N	Procedure terminated, mannitol, eye massage	Close follow-up

Abbreviation: AEA, anterior ethmoid artery.

^a Includes intra- and post-operative management.

Discussion

Endoscopic sinus surgery is one of the most prevalent surgeries performed in the United States. ¹ The safety profile of ESS has improved significantly over the last 30 years. ^{4,7 -9,11,12} The first publication outlining ESS complications appeared in 1987 with a self-reported rate of 29%. Two years later the principal investigator reported a complications rate of 17%. ^3,4 As endoscopic technique advanced, a review of 2108 patients in 1994 identified a still lower rate of 6% to 8%. ⁷ More recently, database studies analyzing a wide swath of patients undergoing ESS identified a major complication rate of 1% to 3% with an orbital complication rate of 0.09%. ^8,9 The decreasing complication rate over time results from increased surgeon experience, widespread adoption of ESS in training programs, improved diagnosis, and technological advancement among other reasons. ^12,13 Despite this excellent safety profile one must consider the sheer volume of ESS, and the fact that a relatively rare complication rate can translate to thousands of complications annually. It is imperative to continue our drive to minimize complications during sinus surgery, especially given the “high priced real estate” of surrounding anatomical structures.

The current frequency of orbital injury can vary from 0.02% to 6.6% of cases. ^{9 -11,14 -23} A systematic review of 42 studies of ESS in the setting of nasal polyposis between 1994 and 2004 demonstrated an orbital hematoma rate of 0.15%, orbital penetration and fat exposure rate of 2.1%, and diplopia (either temporary or permanent) in 0.3%. ¹⁰ A large study by Suzuki et al in 2015 of more than 50 000 patients undergoing ESS found the highest rate of orbital injury (0.15%) in the subgroup of patients undergoing both ethmoidectomy and maxillary antrostomy. In this same study, all-comers were noted to have an orbital injury rate of 0.09%. ⁹

Orbital complications may include nasolacrimal duct injury, orbital hematoma, extraocular muscle injury, enophthalmos, orbital emphysema, optic nerve damage, and blindness. The orbit is most commonly entered during the ethmoidectomy portion of ESS. ^{2,14 -17,21-23} Rarely, the orbit can be entered mistakenly during maxillary, frontal, or sphenoid surgery. Orbital fat prolapse can herald further disastrous orbital complications such as extraocular muscle injury, muscle entrapment, orbital hematoma, oculomotor nerve injury, or orbital fibrosis. ¹⁷ Oculomotor dysmotility noted postoperatively can occur with orbital fat prolapse and subsequent fibrous connections with extraocular muscles. The most commonly injured extraocular muscle is the medial rectus, followed by the inferior rectus and superior oblique muscle. ^9,14,15 Orbital fat exposure is not well-documented in the literature with limited reports of orbital fat herniation ranging from 0% to 3.6% as outlined by Dalziel et al. ¹⁰ However, there is a clear clinical association of orbital fat herniation with further orbital complications. In our current study, a robust response from practicing rhinologists demonstrate the principle that orbital fat exposure can herald more gut-wrenching orbital complications such as: orbital ecchymosis, orbital emphysema, orbital hematoma, extraocular muscle trauma, and blindness.

An overwhelming majority of cases identified in the retrospective portion of this study resulted in no complications. Each case of lamina papyracea violation with fat exposure occurred during maxillary antrostomy or ethmoidectomy. This was related to overaggressive surgical manipulation adjacent to the thin lamina papyracea. Fortunately, only 7 of the 25 identified patients experienced complications following orbital fat exposure. Five of the 7 cases with complications occurred during revision cases. In 5 of these 7 cases, the complications were minor—limited to bruising, crepitus, or eyelid edema. Only 2 of the 7 cases with complications were considered major, with temporary vision changes (these cases took place in 1986 and 1993). During both cases mannitol was administered, eye massage was performed, and ophthalmology consults were obtained. A lateral canthotomy was performed in a single case in which a retrobulbar hematoma was suspected from a retracted anterior ethmoid artery bleeder. In addition, an external anterior ethmoid artery ligation was undertaken to further control bleeding. This surgery took place in 1986. There were no cases of permanent vision changes.

Anecdotally, the estimated cases numbers of orbital fat exposure during our institution’s rhinology training program is about 2 to 3 annually—translating to larger number of cases represented in this retrospective review. We suspect the 25 cases identified were more likely to be discovered due to the complications surrounding orbital fat exposure. The inadequacy of existing codes for orbital fat exposure resulted in unidentified cases, with a bias toward uncovering those which resulted in complications. This has the potential to falsely inflate theorbital complication rate following orbital fat exposure.

There is a clear consensus among rhinologists responding to this survey that intraoperative diagnosis of orbital fat herniation relies upon endoscopic appearance and the bulb press test (Figure 2). ^2,13 The bulb press test is simple, easy-to-perform, and highly specific to confirm violation of the lamina papyracea during ESS. We gladly note that only a few rhinologists perform the “Fat Float” test to diagnose orbital fat, which was more commonplace in the late 1980s and 1990s. The Fat Float test takes a biopsy of possible orbital tissue where lamina dehiscence is questioned. If the tissue is placed in saline, fat will float, while non-fat tissue will sink. Therefore, if tissue sinks the surgeon presumes it is okay to proceed with surgery. Unfortunately, the fat float test can lead to false negatives which can be catastrophic. If an area of suspicion for entrance into the lamina papyracea is identified and herniated tissue is biopsied that does not float, then theoretically it is okay to proceed with surgery. However there have been anecdotal cases when the “tissue” removed was sent for pathology only to reveal muscle on postoperative diagnosis.

Figure 2.

Bulb press test (artist credit: Amy Pittman, MD).

Due to these concerns, we recommend performing the bulb press test prior to any consideration of biopsy in cases of thinned or dehiscent lamina. The lamina push test, in which a blunt instrument is used to gently probe the lateral ethmoid wall, has been proposed as alternative to the bulb press test. ²⁴ In this alternative test, if the lamina wall is seen to move as a unit then adequate surgery is complete. If there is little, or no, movement then additional ethmoid partitions can be removed. However, it is the opinion of the senior author that this technique could be hazardous. Local movement of the lamina, as opposed to movement of the entire lamina, may in fact be secondary to locally dehiscent bone or previously exposed fat/orbital contents. In this case, local movement as reason to continue remove ethmoid partitions would be extremely hazardous. The globe push test can more accurately diagnose any lamina papyracea dehiscence and “warn” the surgeon against proceeding and placing the orbit at risk.

Identifying the endoscopic appearance of orbital fat, in concert with the bulb press test, is adequate in most cases. However, this becomes more difficult in cases of extensive disease, especially polyps, where the disease itself may have thinned the lamina, or caused a dehiscence. Careful review of the preoperative imaging can delineate anatomy of concern during ESS. The hypoplastic maxillary sinus with the uncinate process retracted laterally atop the lamina papyracea can easily result in orbital injury if not recognized on preoperative imaging. In addition, the junction of the vertical basal lamella with orbit is the most common area of lamina dehiscence and medial rectus injury (Figure 3). In these areas, the surgeon must be vigilant during dissection and use the bulb press test to assess lamina integrity.

Figure 3.

Coronal and axial slices of CT sinus demonstrating orbital contents in the left ethmoid after previous trauma. CT indicates computed tomography.

Based on a significant portion of respondents, the guiding principle regarding intraoperative management of orbital fat exposure is caution. In the principal investigator’s early ESS experience, the orbital fat was manipulated (eg, trimmed or replaced). However, this was abandoned due to the higher risk of bleeding, scarring, and further damage with minor dissection of orbital contents. Within the case series, orbital fat was manipulated more often in early career experience, which was a period with more frequent orbital complications in the field of Rhinology. The adoption of a “no further manipulation” principle ushered in a period of cautious/expectant management, and led to a decrease in major orbital complications. Over manipulation of orbital fat carries an elevated risk of causing intraorbital bleeding or trauma to extraocular musculature. This is bolstered by findings in the survey in which >95% of respondents choose caution, limited dissection, removal of the microdebrider from the field, or termination of the procedure to avoid a major orbital complication from orbital fat exposure. If orbital fat is exposed, but not recognized, the inappropriate use of the microdebrider can quickly lead to extensive damage. If the microdebrider is still utilized during dissection, it should be judicious with the jaws of the debrider facing away from the exposed orbital fat. Orbital fat herniation is alarming, but it is ultimately our ally during sinus surgery as an early warning sign.

The evidence regarding patching a defect in the lamina papyracea is lacking. As demonstrated from the survey, a minority of surgeons prefer an absorbable hemostatic agent to act as a patch, physical marker, or barrier, for the duration of the procedure. In large part, observation alone (without repairing the defect) is advocated by the authors.

With regard to postoperative management, this is at the discretion of the attending surgeon. In the senior author's experience, cases of orbital fat exposure that have been properly identified intraoperatively can be expectantly managed with cautious observation in the recovery room. Should orbital hematoma or other orbital injuries occur during surgery or in PACU, then medical or surgical treatment should be implemented immediately. These have been described in several prior publications by the senior author. ^{2 -6} Closer follow-up, or telephone encounters, can be considered based on the extent of the injury. It is reasonable to assign routine postoperative follow-up to patients with a small breach and no concerning signs or symptoms in PACU. Postoperative observation for orbital hematoma development and a deliberate review of sneezing and nose blowing precautions should be explicitly discussed with the patient and family prior to discharge. Delayed orbital hematoma or subcutaneous emphysema can occur after discharge. Thus, an appropriate plan of action can be implemented should a problem arise. Lastly, if future revision endoscopic sinus surgery is needed on a patient with a history of dehiscence or orbital fat exposure caution is advised. However, in the experience of the senior author, the lamina papyracea has sealed itself with firm scar decreasing the risk of repeat orbital fat exposure.

As Han outlined well, the best way to minimize orbital complications from lamina papyracea breach is with a thorough preoperative assessment, critical review of imaging, identification of anatomic variants, and astute visualization of orbital fat confirmed with the bulb press test. This current study offers a practical guide from experts in the field regarding diagnosis, intraoperative, and postoperative management when orbital fat is exposed during ESS.

Conclusions

Orbital fat exposure during ESS is not often discussed in Otolaryngology literature. However, it is relied upon by virtually every Otolaryngologist performing ESS as harbinger for major orbital complications. Orbital fat herniation during ESS should be recognized by endoscopic appearance and confirmed with the bulb press test. Caution with further manipulation of orbital fat herniation is the guiding principle for intraoperative management. Finally, postoperative management is oftentimes conservative, with an expectant management of more serious orbital complications.